PDF Archive

Easily share your PDF documents with your contacts, on the Web and Social Networks.

Share a file Manage my documents Convert Recover PDF Search Help Contact



Graphical Analysis Electric Survey of old Well Logs .pdf



Original filename: Graphical-Analysis-Electric-Survey-of-old-Well-Logs.pdf
Title: GraphicalAnalysisESWell Logs.PDF
Author: opa, Otis P. Armstrong, PE

This PDF 1.6 document has been generated by GraphicalAnalysisESWell Logs.doc - Microsoft Word / Acrobat PDFWriter 4.0 for Windows NT, and has been sent on pdf-archive.com on 19/07/2013 at 12:52, from IP address 118.172.x.x. The current document download page has been viewed 690 times.
File size: 412 KB (13 pages).
Privacy: public file




Download original PDF file









Document preview


Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Abstract
Here is a method for qualitative analysis of Electrical Survey (ES) logs. The basis of the
method is detailed in1, “Water Saturation & Productivity Estimates from Old Electrical
Survey Logs of Clean & Shaly Sections”(www.oiljetpump.com). Systems of interpretation
for ES logs (SP, Rn, Rlat, typically SP, R16, R64, R18-8”) are sparse. Mainly due to
advances in logging systems to overcome inherent problems of the ES system. However,
many (perhaps6 40%) of American wells were logged using the ES system. The analysis
method is to plot log(R16/Rd) vs PSP, with Rd as an interpolated value from either Long
Normal or Lateral. This is similar to analysis by plotting log(Rxo/Rt) vs SSP. However
many old wells were not logged with a Rxo tool, subsequently Rxo is indeterminate from
ES data, but R16/Rd is available from the ES log. A Neural network was used to map
charts in place of using least squares regression.
Background
Schlumberger2 presents Chart D12, “Saturation Determination 5FF40 - 16” Normal, Thick
Beds of Low and Medium Resistivity”. Schlumberger used a modification of the SP
equation as their basis of analysis. The shale PSP equation is:
Sw = {(Rxo/Rt)/(10(PSP/K))}(5/a 8)

& PSP = a(SSP) & if a =1, PSP=SSP

This equation plots linear with Rxo/Rt plotted on a log scale vs inverse PSP on a linear
scale: PSP = Klog(Rxo/Rt) - K1.6alog(Sw) This plot is linear passing thru the point
PSP=0 & Rxo/Rt=1, with a series of Sw lines thru same point.
With the ES, Rxo is not generally available. The invaded zone resistivity, Ri, can be used
instead to calculate Sw by inclusion of mixing factor1, z,

Sw ={(Ri/Rt)[Z + (1-Z)/(10(PSP/K))]}(5/a8)

A plot of log(R16/Rt) is not linear against PSP but an alternative is feasible, given the
nearly linear nature of log[Z + (1-Z)/(10(PSP/K))], plot 1.

Schlumberger’s approach2 in Chart D12, plots log(R16/Rd) vs PSP, allowing the Sw line to
curve rather than be linear, as would be the case for a SP plot. The Sw curvature
accounts for mixing and invasion effects. In chart D12 Rd is R(5FF40) and in chart D14,
Rd is R(6FF40), p254 Pirson3.
In analysis of ES logs, it is proposed to use Rd evaluated from long normal or lateral
values in place of the induction value. Using the best response of either R64 or R18-8”,
should give a qualitative analysis of Sw. False positives are reduced by consideration of
ES response properties.
The depth of investigation for R5FF40 is similar to R64, and R6FF40 closer to R18-8. This
is seen by looking at Lane Wells interpretation charts for R16 vs R64 and R16 vs R18-8

1

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
and comparing to similar charts for R16 vs 5FF40 and 6FF40, pp89-92, 105-108, 169-172
of Pirson. This comparison is shown in Appendix 1, 2.
All other factors being equal invasion diameter, Di, is related to porosity. Pirson’s
interrogatory is: “ invasion distance depends not just on porosity but mud filtrate rate,
differential pressure, time of exposure & back diffusion.” When using only two logs,
(thin beds e<72 inches) a porosity balance gives additional check on analysis validity.
Critical line
The Critical line is Schlumberger’s production cut-off limit for sandstone. It corresponds
to a water saturation of 50% for Di/dh between 3 and 5, and 60% for Di/dh<3.
Use 5FF40 critical line for Long Normal, R64, and 6FF40 for Lateral resistivity, R18-8 deep
resistivity, see Appendix 1. The critical line is calculated by regression equation: If R16/Rd
> Critical, then likely condition is water, at given PSP. The critical ratio at SSP of -55 &
100F, for R16/5FF40 is 1.55 and for R16/R6FF40, is a ratio of 1.8.
Tool
Critical Lines at 100F, other T use Rmf/Rw=
PSP range
Tool=
R16/R5FF40
R16/R6FF40

-0.5+10^(0.00005*PSP^2 + 0.0001*PSP + 0.1635)
10^(5/100000*PSP^2 - 0.0028*PSP - 0.053)

>-140 & <0
>-140 & <0

R64
R18-8

APPLICATION
For Shaly sands Schlumberger method draws a line from PSP=0, R16/Rd =1 to PSP and
R16/Rd. A projection of this line, on semilog grid, intersecting with SSP indicates water
saturation, in terms of effective porosity. An example is shown in Graph 2 at PSP of -30
and SSP of -90. In shaly sections, this water saturation in terms of effective porosity is
always less than that calculated on total porosity. For the example line of Graph,
indicates a productive section, provided SSP exceeds -80 for the 6FF40 and -100 for the
5FF40 line. Analytical solution of the method is made by application of similar right
triangles principle, (A/C)1=cos-1(?)=(A/C)2
Water Line
An SP’s plot of water line is linear, shown on Graph 2. However, the water line plot of
R16/Rd vs. PSP is curved. Such a water line (not shown on Graph 2) corresponds to
R16/Rd approximately 1.4 times greater than the critical value.
Additional qualifications given for the method of Schlumberger are
1
?? for R16/Rd <1.2 use Archie equations
?? method applies only to permeable beds,
?? do not use method if Rmf/Rw is less than Di/dh.
Comparison of Ri/Rt of ES Tool and FF40 Tool
A set of analytical equations for Sw using ES log was proposed by Armstrong1, using
Lane Wells invasion charts2 89-105 to solve Ri and Rt. Table 1, below provides a
summary of these equations. Details of the quantitative method, and a calculation
spreadsheet are given in the reference 1. A similar set of Lane Wells invasion charts2
pp 169-171 are available for R16 and RFF40 and the equations are also valid for these
charts.
2

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
TABLE 1
(aSSP/K)
Sw = {(Ri/Rt)[Z + (1-Z)/(10
)]}(5/a8)
Eq.1
[Z2.62(10(SSP/K)-1)+Z1.62](1-2Z)2 -Rmf/[(Ft/Fa)2.5Ri]=g(Z)=0 Eq2
Ft/Fa = 10^[(a - 1)SSP/K]
Eq3
Ft = {Ft/Fa}[Ri (1-2Z)2]/(Rz)
Eq4
(SSP/K)
Rz = Rmf/{(10
)Z + (1-Z)}
Eq5
a = PSP/SSP
K=-(oF/7.6 + 60.5)
Eq6
PSP is (a * SSP) and if log[Z + (1-Z)/(10(aSSP/K))] vs PSP is close to linear scale then
plotting PSP vs. log(Ri/Rt) will allow a qualitative analysis of ES data. The below plot shows near
linear fit at maximum expected Z, and as Z decreases, the linearity also increases. This concept
is used in Schlumberger method for R16/RFF40.
0

A lm o s t L in e a r
z = 0 .2 0 , K - 7 5

-1 0

f(ASP/K,z)

-2 0
-3 0
-4 0
-5 0
1 0 0 lo g (z + (1 -z )/1 0 ^A S P / K )
L in e a r (1 0 0 lo g (z + (1 -z )/1 0 ^A S P / K ))

-6 0
-7 0

A S P
-8 0

-7 0

-6 0

-5 0

-8 0
-4 0

-3 0

-2 0

-1 0

0

The effect of decreasing water saturation is seen in the below plot of PSP and Ri/Rd vs PSP for
Sw=1 and Sw=0.50, as are the critical lines of Schlumberger.
S=1 a=1 Doll
Doll S=0.5 a=1
5FF40 Critical
6FF40 Critical
Shale Soln PSP-30 SSP-90
GRAPH 2

R16/Rd K=-75

10.0

PSP

1.0
0

-20

-40

-60

-80

3

-100

-120

-140

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Considerations in plotting R16/R64 or R16/R18-8

R16 is not same as Ri (invaded zone resistivity), it can read anywhere between Rt and Rxo,
depending on type of formation. In the case of low porosity formations R16 will read closer to
Rxo. In the case of very low resistivity formations R16 will read closer to the deep resistivity. If
R16 approximates Rxo, then plotting R16/Rd vs PSP imposes no special considerations, as the
plot reverts to a classic SP plot. Use of R16/Rd vs PSP as a qualitative tool requires only a
reasonable contrast between R16 and Rd. The more serious drawback is associated with
reading Rd by the Long Normal, R64. There are fewer considerations in reading Rd with the
Long Lateral R18-8 due to the increased reading depth of electrical signals with this tool.
Considerations for borehole and bed thickness are provided in the spreadsheet. For R16, chart
B12 Borehole and Bed Thickness correction factor was mapped by neural network. Chart B12
applies for Di/dh between 2 and 10, as is typical of medium to high porosity beds.

Long Normal, R64. (AM typically 64 inches)

If resistive bed thickness is less than AM (64 inches), the tool records an inverse crater. The
distance between the crater rims being bed thickness plus electrode spacing, (e+64, for R64
inch normal and e+16 for the short normal). When bed thickness is greater than AM, normal
tool readings are distorted in the area +/- (½AM) from both actual bed top and bed bottom.
Borehole and thickness factors are provided in the spreadsheet, using either Hilchie method or
Guyod charts to correct bed thickness and Schlumberger charts for borehole effects.

Deep Lateral, R18-8, (AO typically 18’-8”), also called R19 or R20

The conventional lateral responds to beds as thin as 16 inches. In resistive beds less than AO
a nick 16 inches above bed top and a reflection peak located at e+18’-8” below bed top will be
present. Also for thin beds there is a dead zone for 18’-8” below the bed top, in which zone the
lateral reading is not analytical. For e> 19-20 feet, a decay zone exist AO feet from bed top.
Borehole and thickness factors are provided in the spreadsheet, using either Hilchie method or
Guyod charts to correct bed thickness and Schlumberger charts for borehole effects.
In overcoming the various problems of the ES tools, it is chosen to use the max value from R64
and R19. After plotting, eliminate those points associated with tool anomalies, as mentioned
above.

Porosity Balance

A porosity balance is recommended to confirm result. The porosity balance consist of
determining formation factor, F, by the equation: F = (Ft/Fa)RtSw2/Rw . The porosity balance is
essentially a consistency check, for Sw results of the ratio method, the essence of Charts D12
and D14. If a formation is clean, PSP=SSP, and (Ft/Fa) is unity. Various accessory routines are
given in the workbook “CF_Conv_Sw(F)”, to assist in calculation of F, provided R16 reads Ri and
Rd reads Rt. Evaluation of this last assumption is given in the spreadsheet dealing with
invasion charts for ES logs.

4

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Summary
Plot of R16/Rd of ES logs vs. PSP will compare favorable to a similar plot using
R16/FF40 because investigation depths of the FF40 tool compare to Long Normal, R64
and Lateral R18-8. However unique features of response signatures for R64 and R18-8
tools must be reconciled for a best evaluation.
1
Compare ES Calcs toSchlum Chart D12 D14
37 points 1 false positive

hil3000n
hil2040L

w x10930n
w x9217n

w x9217L
olm3784L
and7446n
UC1940n olm3784n
G5630L
G5045L
Fri7080n
anv1520LAnv1520n
Fri7080L
DJ6660n
plq9530L
DJ4696N
RF3050n
Txlr5.12L
G5650L
anv33corN
G5650n
Mlsh7994n
G5630n Spr8860Lplq9530n
MC3520
andk16376n
spr7030n
spr10600n
Parity
Schlum D12&14

0.5

Spr9420n

0
0

0.5

1

Additional sections were added into the spreadsheet to make ancillary calculations
related to porosity balance given in the workbook “CF_Conv_Sw(F)”.
References
1. Armstrong, O.P. 2005, Water Saturation & Productivity Estimates from Old
Electrical Survey Logs of Clean & Shaly Sections” www.oiljetpump.com
2. Schlumberger, 1966, Log Interpretation Chart Book. Schlumberger Well
Surveying Corporation, Houston TX
3. Pirson, S.J., 1963, Handbook of Well Log Analysis, Prentice Hall, NJ
4. Pirson, S.J., 1957 Formation Evaluation by Log Interpretation, World Oil GPC,
Houston Tx April/May /June 1957, wide range of topics relative to older logs
& oil/water mobility in various reservoir rock types, including shaly reservoirs
5. A2D.com source of well logs reviewed for this study
6. Hilchie DW 1979 Old E.Log Interpretation, pre1958, AAPG reprint 2003 Tulsa, p2
7. Guyod,H. 1945, Location of Sand type Reservoirs Oil Weekly Vol.120 No.1, Dec.3,
reprinted in Guyod, H. 1952 Electric Well Logging Fundamentals, p132 , Widco
Instrument. Houston TX

5

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Appendix 1
Since true resistivity is a property of the formation, a comparison of apparent tool resistivity to
Rt will show difference in Ra for various tools. Here are comparisons of tool response of R64 to
R5FF40, Low Resistivity Formations using Lane Wells invasion charts, p169, p89 Pirson. The
response of these tools typically differ by less than 5% in most conditions. The comparison
result is not surprising as 5FF40 tool was actually designed to mimic R64 investigation depth.

R5FF40/R64

1.10

Compare Response Low R formations, Di/Dh=2

1.05

1.00

Rt/Rm=1.5

Rt/Rm=2

Rt/Rm=4

R16/Rm

0.95
2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

Appendix 2

Compare tool response of R18-8 to R6FF40, Low Resistivity Formations using Lane Wells
invasion charts, p171, p105 Pirson. The response of these tools typically differ by less than 5%
in most conditions. The 6FF40 tool was actually designed to mimic R19 investigation depth.
1.09
R6FF40/R19

Compare Response Low R formations, Di/Dh=2
Rlateral vs R6FF40 ind.

1.04

Rt/Rm=1.5

Rt/Rm=2

Rt/Rm=4

0.99

R16/Rm

0.94
2

3

4

5

6

7

These graphs indicate an error of less than 3% is expected if charts D12 & D14 are used with
the corresponding ES tools to calculate Sw. This is because Sw is nearly proportional to square
root of Rt and the 6&5-FF40 tools respond to within 5% of ES deep tools. The root of 1.05 is
about 1.025.

6

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Appendix 3 Application to ES of Riley-Surrat of Cross Co. AR
Riley Surrat Well Log Plotted vs depth
15

Riley-Cross Co. AR es log

RN.16"om/m
RN.64"om/m

13

R.Lat 18'-8"
mv SP/10

11
9
7
5
3
1

2120

2170

2220

2270

2320

2370

2420

2470

2520

-1
-3
-5

15

RN.16"om/m

Riley-Cross Co. AR es log

RN.64"om/m

13

R.Lat 18'-8"

11

mv SP/10

9
7
5
3
1

2120

2130

2140

2150

2160

2170

2180

2190

2200

2210

2220

2230

2240

-1
-3
-5

7

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
A plot of the well log for Riley-Surrat is used for illustrative purposed. At 2220 a classic thin
high resistive bed appears, with 96” separation between LN crater rims. Bed thickness is 96
less 64 or 32inches. The reflection peak appears at 2240 on lateral. Symmetrical properties of
normal curves indicates bed center at 2219, bed top 2217.5, base 2220.5. Inflection of SP
curve is noted at 2217.5, 2219, 2222. Another anomaly appears at 2502, LN crater rims are at
2497 and 2505, t =24 inch.

Plot R16/Rd vs PSP for Well Riley Surrat

1.30

2286
2130

2131
2508 2500

2499
2215

2132

2340
1.20

2282
2281

2230 2223

2317 2310
2365
2370 2550
2266
2262
2264 2492
2450
2308
2261
2545
2305
2470
0.80

2207

2514 2512
2490
2506
2516
2395

2236

2155
2137
2136
2175
2153

2185 2190
2181
2195
2180

2498

2151

2178

logR16/Rd RS X-Co AR

25022504

Critical

2220

2240

2148
2146
2144
2173 2150
2162
2140
2141
2138
2166
2160
2170
2158
2156

2202
2200
2192

2518
2485
2494
2520
2510
2535
2219
2538
2493 2501
2496
2525

2260
2254 2246
2256
2248 2245
2530
2540
2250
2259
2380

2134
2135

2210

2426
2273

2350
2465
1.10
2120 2390
2400
2268
2455
2278 2289
2330
2460
2410
2295
1.00
2420
2425
2430
2290 2453
2298
2352
2475
2300
2270
2296
2320
2440
2415
2304
2375
2445 2355
2360
2405
2385
0.90

0.70

2133

Ri/Rd

2124
2122
2127
2129
2126
2128
2480
2125

Critical
-PSP

0.60
-5

-15

-25

-35

8

-45

-55

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Appendix 4
In case presented here, it is not possible to reach an exact solution using one set of
invasion charts (either 2 normal or R16 and deep Lateral). For this case, solving
Formation Factor, (F porosity balance), and Sw for each value of Ri and Rt does give
insight into validity of data, if some idea of lithology is understood. The most direct
method is solving F based on deep resistivity. The method gives additional insight
when only one set of invasion charts can be used, such as in thin beds with Electrical
Survey tool.
1) Solve zn using Newton-Ralphson iteration
Assume ROS is not dependent on Z, as used by Pirson, then g(Z) and g’(Z) allow
implicit evaluation of Zn, given, chart value of Ri/Rm, alpha (determines Ft/Fa), SSP,
Rmf/Rm and temperature.

g’ = [2.6Z1.6(Rmf/Rw - 1)+ 1.6Z0.6](1-ROS)2 ]

Eq.2c

g(Z)= [Z2.6(Rmf/Rw-1)+Z1.6](1-ROS)2 -(Rmf/Rm)/[(Ft/Fa)2.5(Ri/Rm)n]=0

Eq.2b

Take initial value of Z as 0.41/[abs(Rmf/Rw-1)^0.26(1-ROS)(SQRT(Ri/RmFt/Fa)] and solve
forward until g(Z) approaches zero. In this instance. n refers to the values of Z and
Ri/Rm for each invasion chart. A neural network map of invasion charts is provided in
spreadsheet1, for R16/Rm less than 25.
2) Solve Sw(n)
Sw(n) = [(Ri/Rm)n{[zn+(1-zn)/10(PSP/-K)]/(Rt/Rm)n}]1/(1.6a)
Where n, represents the invasion chart, Di/Dh of 2,5,10 or 15.
3)Check value of F
Fd = (Ft/Fa)(Sw)2Rt/Rw and Fi = (Ft/Fa)(1-ROS)2Ri/Rz
If a reasonable solution is provided, the ratio of deep formation factor, Fd to invaded
formation factor. Fi will be close to 1 and Fd will be close to anticipated value.
For high porosity formations Rd approximates Rt and porosity balance is effected using
Rd, thereby eliminating evaluation of Ri and z.

9

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Appendix 5 Discussion of spreadsheets

MID Plots,
The purpose of mineral identification is to better ascertain mineral bulk property for calculating
porosity and formation factor, F. These systems are best expressed in Matrix form. The
Gypsum, Anhydrite, Dolomite, system is shown below as a matrix form, from Wylie p178:

F

G’

A’

D’

tG

tg

ta

td

?G

?g

?a

?d

1
1

0.49
1

0
1

0
1

RHS
t bulk

<=Variable/Description
Sonic Matrix Coeff

? bulk
FN
1

Density Matrix Coeff
Hydrogen Matrix Coeff
Mass Matrix Coeff

Systems of two components may be expressed in similar way, i.e. Limey-Sand:

F

S’

L’

tG

td

tL

?G

?d

?L

1

1

1

RHS
t bulk

<=Variable/Description
Sonic Matrix Coeff µSec/ft

? bulk
1

Density Matrix Coeff g/cc
Mass Matrix Coeff v/v

tG

sonic travel time of liquid, µSec/ft
?? ? G
density of liquid g/cc
?? F
total porosity & open pore = F - SF s, F s-> shale porosity
?? S
Sand
L
Lime
S
Shale G
Gypsum
?? t d
time Sand
tL
time Lime
tS
time Shale)
?? ? d
Den Sand
?L
den Lime
?S
Den Shale)
?? t
bulk sonic time µSec/ft
?
bulk den g/cc
?? k
Factor of neutron porosity increase for Shale Volume due to chemical hydrogen.
Approximately 14 percent shale volume is taken to add 2% to hydrogen porosity. Pirson
p28, 180, 201.
?? S’ =(1-F )S
L’=(1-F )L
S’= (1-F )S G’= (1-F )G
??

Sand Lime Shale System

F

S’

L’

S’

tG

td

tL

tS

?G

?d

?L

?S

1
1

k
1

0
1

0
1

RHS
t bulk

<=Variable/Description
Sonic Matrix Coeff µSec/ft

? bulk
FN
1

Density Matrix Coeff g/cc
Hydrogen Matrix Coeff Hpor
Mass Matrix Coeff v/v

These are linear systems, solved by inversion of Left Hand Side, as V=(LHS)-1(RHS)
Plots of M-N, por-N vs either density or sonic time, and density vs sonic time may be used for
mineral identification. Options provided for common combinations of sediment rocks are GAD,
Shale-Limestone-Sandstone, Shale-Lime-Dolomite, Lime-Sand, Lime-Dolo.

10

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Appendix 6 Details of Shale Properties
Shale properties are highly variable, but for Type
Density F=Rs/Rw dt, µSec/ft

purposes of these calculations divisions are Gumbo
2.1
5.0
170
given by following Table: Shale Formation Gulf 6k'
2.35
11.6
113
Factor were taken from Guyod p77 and sonic MidCont
2.45
62.5
78
times by Pirson formula p226, F=500/(dt-70).
Shale density were taken from excess pore pressure studies, but overlap of properties may
occur. A conversion from Porosity method to F is made using inverse square rule for
carbonates and Humble formula for sandstones. Shale volume, S or Vs, porosity, if any, is
subtracted from total porosity with open porosity based on: F o=F ? - SF s, F s-> shale porosity,
with shale porosity taken from drop down menu of L43 in sheet 3, Pirson p203. The shale
volume, S, used for correction of open and total porosity is taken from selection of PSP and SSP

Appendix 7 Reference to Calculation Calibration Data Sets

Below is list of calculation and calibration data sets given used in the spreadsheets. Following
these examples will assist the user to grasp program methods, limitations, and capacity.
Example Calibration

Source

Page Sheet

Cell

Source

GAD Matrix calc

Asquith

161

4

Q1

F Cssp

Schlumb.

B1

3

T71

Shale Vol

Meehan

217

4

Q19

Fsonic

Schlumb.

D19b

3

W72

Por & M-N

Meehan

223

4

W1

Fsonic Sch D19-a

Schlumb.

D19a

3

W82

Vshale

Asquith

91

4

W25

F neutron

Schlumb.

C15

3

T78

Matrix Prop (dt den por-n)

OPA

Matrix clc

4

AA2

F by Den

Schlumb.

C15

3

Q77

Open Porosity

Asquith

193

4 AA12

Sonic p

Schlumb.

D21c2

3

Q84

ND Por eval

Asquith

85

4

W33

Sonic por

Schlumb.

D23

3

T95

Por by ND

Asquith

87

4

w41

Fsonic

Schlumb.

D19c

3

W92

Por-n-d Method

Schlumb.

C27

4

T43

Sonic p

Schlumb.

D21b2

Por-n & dt Method

Schlumb.

C23

4

T34

Sonic p

Schlumb.

D21c2b

3

Por-n & Den Method

Schlumb.

C21

4

Q34

F(Ro)

Pirson

93

3

J71

Por-n-d Method

Schlumb.

C25

4

Q41

Implicit Solve Sw(Ro)

Pirson

93

3

M71

Rw(SSP Rmf T)

Asquith

33

3

Q20

Gas sat n-por g-hole

Pirson

259

3

A73

SP->SSP

Asquith

33

3

T20

Gas sat n-por g-hole

Schlumb.

D25-A

3

B73

R64 corr'd

Guyod

139

3

W20

Gas sat n-por g-hole

Schlumb.

D25-B

3

C73

Depth T corr & R Tcorr

Schlumb.

A3

3

Q28

Gas sat n-por g-hole

Schlumb.

D25-C

3

D73

R16 corr'd (Rs Rm e)

Schlumb.

B11

3

T28

R16.dh.RmCF

Schlumb.

B1

3

w41

R19 corr'd for e

Guyod

140

3

W27

R19.dh.Rm CF

Schlumb.

B1

3

w49

R Lateral e CF

Guyod

39

3

W34

R64 dh.Rm CF

Pirson

Fig 7.9

3

T46

R16 corr'd (dh Rm)

Schlumb.

B1

3

W41

Rw(SSP Rmf T)

Schlumb.

A9-12

3

Q48

R19 Dh Rm

Pirson

Fig8.9

3

T37

R16 corr'd (dh Rm)

Hilchie

Fig3.8&3.9

3

Q55

Rw(SSP Rmf T)

Schlumb.

Hilchie Corr'd R18-8

Hilchie

Fmicrolog

Schlumb.

Page Sheet

Cell

Example Calibration

3 Q104
Q94

A9

3

Q41

Sw F R16 R64 SSP

Hilchie

71

3

w58

38-39

3

Q63

Hilchie Corr'd R64

Hilchie

71

3

T63

C2

3

Q71

Data for another 53 Sw calculations are given for comparison to the proposed method in Sheet
2

11

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
APPENDIX 8
Examples Sw & Rw by Implicit Solution via F
method, use sheet3 of spreadsheet.
For
estimation of matrix property, use linear relation
of d(por) with either d(usec or SG) to estimate at
por=0.
Note that F(por) is based on total porosity but
open porosity is (total porosity)(1-Vsh) and is
used in shaly method, Simandoux and duel
water.
Additional examples are found in sheet 3 at cell
Z1. These examples detail Pickett Cross plot and
Hingle Cross plot methods.
The crossplot
methods relate to Matrix identification (MID),
Rw, and Sw.

Ref/page

P.291
P273
p298
p297
p291
p289
p289
p289
M229
M229
M230
M230
M230
A193
W124
W124
W184
W184
W189
W189

D. ft

7080
9868
9425
3050
3050
3050
ex#1D
ex#2b
ex#3a
ex#3a
ex#3a
1926
Fig21
Fig21
Fig34
Fig34
Fig35
Fig35

Sw Sw calc Set Cell
0.66 0.66 H53
0.52 0.50 H53
0.54 0.54 H53
0.21 0.21 H53
0.09 0.09 H53
0.27 0.21 H53
0.27 0.17 N40
0.27 0.27 H53
0.99 1.00 H53
0.37 0.39 H53
0.26 0.29 H68
0.26 0.26 e68
0.19 0.19 h68
0.67 0.65 h68
1.00 1.00 H53
0.52 0.52 H53
1.00 1.00 H53
0.45 0.49 H53
1.00 1.00 H53
0.63 0.62 H53

P=Pirson Well Logs, p=Pirson Resvr Engi M_Mehan A_Asquith
Ref/page W=Wyllie

P.291
P273
p298
p297
p291
p289
p289
p289
M229
M229
M230
M230
M230
A193
W124
W124
W184
W184
W189
W189

psp=-50, ssp-117, Rxo3.65, Rw=0.035,ROS0.15,Rt=1.67Rmf=0.65
SSP=PSP=-77 Rxo32.4, Rw0.40,Ros=0.15Rmf2.35Rt16
psp=-20,SSP=-69 ROS=0.25 Rt=2.25 Rw=0.06Rxo=2.06Rmf=0.42
SSP=PSP=-100 Rt=125,Rw=0.02 Ro=5.6
SSP=PSP=-92Rt=112Rw=0.033R2"=4Rm=0.70
ssp=psp=-92Rt=17Ri=40Rw=.042Rmf=1.12Rm=1.4
ssp=psp=-92Rt=17Ri=40Rw=.042Rmf=1.12Rm=1.4
ssp=psp=-92Rt=17Ri=40Rw=.042Rmf=1.12Rm=1.4Ro=1.15
por=.091Rt=4.2Rw=0.039
por=.154Rt=6.7Rw=0.029, Mehan selected Consol SS this routine has only generic sandstone
por=.154Rt=7.5Rw=0.018, Rsh=1.1 Vsh=0.15(setsPSP=85SSP=100) F2w method
por=.154Rt=7.5Rw=0.018, Rsh=1.1 Vsh=0.15(setsPSP=85SSP=100) Fsimdx snd method
por=.154Rt=7.5Rw=0.018, Rsh=1.1 PSP=-20SSP=-48 F_2w snd method
por=0.18Vsh_0.09Rsh4Rt11Rxo16PSP-52SSP-57 avg Simdx&2W
Rw(ND 35/1) Ndmin=100NDmax=1300ND(S=1)=300,R(S=1&300ND)=2.5 Get Rw=0.092
Sw(w/Rw above35/1carb) Ndmin=100NDmax=1300ND(min)=300,R(S&500ND)=30 w/Rw=0.092
Rw(dtmax) dt=62 R=18 Get Rw=0.105
Rw=0.105 Rt=6 dt=87
Rw(Sw=1,Sg=2.49)Rt=5.5=>Rw=0.066
Sw(SG=2.4 Rt=5.5, Rw=0.066) NaCl SS

12

#
E59
E59
E59
K68
H47
K39
K39
E59
B61
B61
B61
B61
B61
B61
K46
K46
K56
K56
H60
H60

Chg cell

H52
H52
H52
H52
H52
H52
N39
H52
H52
H52
H67
e67
h67
h67
F38
H52
F38
H52
F38
H52

Graphical Analysis of Electrical-Survey Well Logs of Clean & Shaly Sections
Otis P. Armstrong P.E. Jan 2007.
Definitions
PSP, psuedo static potential of a thick shale-sand sequence, PSP=ASP(CF)
CF ASP generic correction factor for bed thickness = 1/(0.2933Ln(e’-feet) + 0.0622), valid
e>2feet and <20feet, chart developed for Gulf Coast type sands7. A neural network model is
included but user must have some idea of lithology or Ri/Rm.
e bed thickness
R16a, apparent value of 16” normal tool at bed center valid e>AM=16”
R64a, apparent value of 64” normal tool at bed center valid e>AM=64”
Rnc Normal sonde corrected for bed thickness
=Rn[1+(ln{Ra/Rs})/(e/AM-1)], valid Rm>Rs/3 & <5Rs, e>2AM
R18-8a, apparent value of 224” lateral tool AO=224”, AN is 20 feet
R19, another short name for R18-8 since 18 ft 8 inches to closest foot = 19 feet

Sonde
Normal
Lat

CF type
shoulder

Equation
Rt/Ra=[1+(ln(Ra/Rs))/(e/AM-1)] e/AM>2
(bRa/Rs)

(b)

Rt/Ra=(a)e
a=1.18-0.376e ,
b=0.83(e/AO)0.56 . valid: 0.1>e/AO <1

Guy. Fig3p139
Guy. Fig6p140

Other correction factors either by regression or by Neural Network model. Confirmation data
given in spreadsheet and referenced by Table of appendix
Additional details of variable names may be found in reference 1.

13


Related documents


h2o sat productivity electrical survey logs clean shale
graphical analysis electric survey of old well logs
waterresistivity
organic matter pore characterization in gas shale by him
17i17 ijaet1117334 v6 iss5 2103 2111
the essentials trend trading techniques


Related keywords